Caption:WASHINGTON, DC - NOVEMBER 19: U.S. Senate Minority Leader Mitch McConnell (R-KY) speaks to reporters following the weekly policy lunch of the Republican caucus November 19, 2013 in Washington, DC. McConnell spoke on continued problems with the implementation of the Affordable Care Act during his remarks.National Journal

Senate Minority Leader Mitch McConnell is asking his fellow Republicans to block a bill that would curtail the government's domestic spying powers. In fact, he doesn't even want the Senate to talk about the measure.

In a statement Tuesday, McConnell said he "strongly opposes" the USA Freedom Act because it would hamper the U.S.'s ability to combat the rising threat of the Islamic State in Iraq and Syria.

"This is the worst possible time to be tying our hands behind our backs. The threat from ISIL is real," the Kentucky Republican said in a statement, using a different name to refer to the Islamic State. "It's different from what we've faced before. And if we're going to overcome it—if our aim is to degrade and destroy ISIL, as the president has said—then that's going to require smart policies and firm determination."

McConnell is "actively whipping" his caucus to not allow the measure sponsored by Judiciary Committee Chairman Patrick Leahy to advance Tuesday, according to a Republican Senate aide who favors Leahy's legislation. The aide suggested that McConnell preferred separate legislation offered by Senate Intelligence Chairwoman Dianne Feinstein and Saxby Chambliss, the panel's top Republican.

The Tuesday vote would open debate on the legislation, but it needs 60 votes to clear a filibuster. With McConnell's opposition, reaching that threshold becomes more difficult, and if supporters can't get there, lawmakers won't be able to offer amendments—and the measure likely won't come up for consideration again before the next Congress.

The USA Freedom Act would effectively end the National Security Agency's bulk collection of Americans' phone metadata—the numbers and time stamps of phone calls but not their actual content. The once-secret program was publicly exposed by Edward Snowden last summer.

The bill boasts support from the tech industry, privacy and civil-liberties advocates, the Obama administration, and Director of National Intelligence James Clapper. But it faces opposition from several defense hawks, particularly within the GOP, and it remains unclear if it has the votes to advance.

McConnell's fellow Kentuckian, Sen. Rand Paul, said last week he will oppose the bill because it does not go far enough and would extend portions of the post-9/11 USA Patriot Act for two years.

Components of the Patriot Act, which gives the NSA much of its surveillance authority, is set to expire next summer, casting doubt on how Congress will approach the issue of government surveillance next year.

Sen. Ted Cruz, one of a few Republicans who supports the Freedom Act, would not comment directly on McConnell's efforts, or on whether the measure had enough support to move forward.

"We'll see where the votes lie," the Texas Republican said.

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